1. Field of the Invention
The present invention relates to a nonvolatile memory cell obtained by using a resistance element that includes two electrode films between which a recording film is sandwiched and that is given voltages having different polarities at its two electrodes to reversibly change the resistance value of the recording film, that is, a so-called nonvolatile variable resistance type storage element, which replaces a p-channel metal oxide semiconductor (PMOS) transistor of a six-transistor-type static random access memory (SRAM) memory cell, or by adding this to a six-transistor-type SRAM memory cell to add a nonvolatile function to a SRAM memory cell, and to a storage device and a nonvolatile logic circuit using the same.
2. Description of the Related Art
A six-transistor-type SRAM cell is one of the most general memory cells in semiconductors and is widely used in memory products and logic products. It is very excellent in terms of high speed performance and stable operation. However, when the power is turned off, the stored information will be erased, and therefore this memory cell cannot be used as it is for a nonvolatile memory.
On the other hand, a flash memory is generally used as a nonvolatile memory, but both of the NOR type and the NAND type are slow in write and erase speeds, taking, for example, 10 microseconds to 10 milliseconds, and are limited in rewrites to about 100,000 times, and therefore may be suitable for data storage applications and file storage applications, but cannot be said to be suitable as general purpose nonvolatile memories.
Further, as a memory system combining different functions, there is a memory combining an SRAM and a flash memory (EEPROM) and backing up information of the SRAM to the flash memory when the power is turned off.